University of PardubiceFaculty of Chemical Technology

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Thermoelectric properties of Cr-doped single crystals Bi2Se3 – search for energy filtering

Authors: Čermák Patrik | Ruleová Pavlína | Beneš Ludvík | Navrátil Jiří | Drašar Čestmír

Year: 2017

Type of publication: ostatní - přednáška nebo poster

Page from-to: nestránkováno

Titles:

Language	Name	Abstract	Keywords
eng	Thermoelectric properties of Cr-doped single crystals Bi2Se3 – search for energy filtering	Thermoelectric effects are one of the promising ways of utilizing of waste heat. The efficiency of the conversion of heat into electricity is given by transport coefficients of a material, Seebeck coefficient, electrical conductivity, and thermal conductivity. However, mutual dependence of these coefficients, which is largely related to the band structure, makes their independent optimizing impossible. Novel approaches have appeared in last decades with the aim to enhance thermoelectric conversion. The theory of energy filtering of free carriers by (nano)inclusions ranks among the latest. Optimally, this could provide increase in both Seebeck coefficient and electrical conductivity and even decrease of thermal conductivity. Although the basic idea is clear, the experimental evidence is rare. Based on this concept we search suitable systems with stable structures showing a hint of the energy filtering. Here, we report on an anomalous behavior of Cr-doped Bi2Se3 single crystals which, we think, is related to energy filtering. We use otherwise un-alloyed single crystalline matrix to avoid any interference of other effects. The solubility of chromium in Bi2Se3 was studied, which is the key parameter in process of formation of (nano)inclusions. The influence of equilibrium temperature is included. We present recent results on the effect of Cr-doping on transport coefficients on a wide set of single crystalline samples including tuning of free electrons due to stoichiometry variations of selenium.	Thermoelectric properties; single; crystals; tetradymite; energy filtering